Aphids. Wash the plant off thoroughly with a strong spray of water.

so just physically remove them one way or another? What will that keep them from coming back?

Surprisingly, usually, yes, if you are thorough. After that you can maintain by using a cotton ball damp with rubbing alcohol if you think you see any more.

Awesome. Thanks everyone for the very quick responses. Love this forum.

If the plant is still fairly small you can wash it under the tap. Just hold it slightly sideways to stop the mix falling out and swoosh the leaves with your fingers.